Core

ABSTRACT

A core includes a winding part, and a wall part including a first wall part, a second wall part spaced apart from the first wall part and disposed opposite to the first wall part, a third wall part in contact the first wall part, and a fourth wall part disposed opposite to the third wall part. The wall part surrounds the winding part.

TECHNICAL FIELD

The present disclosure relates to a core.

BACKGROUND ART

In the related art, a technique in which a combination of two E-shapedor U-shaped cores is used in a transformer provided in a powerconversion apparatus or the like is commonly known. For example, in thecase of the E-shaped cores, each core includes a main body partextending in a predetermined direction and three legs extending in adirection perpendicular to the predetermined direction from the mainbody part, and two cores are used in a transformer in the state wherethe legs of the two cores are opposite to one another.

For example, a configuration in which an E-shaped core and an I-shapedcore are coupled is known as a related art. In this configuration, eachcomponent is fixed so as to maintain the relative positions. Inaddition, in the case where a gap is provided between each leg of eachcore of the transformer, E-shaped cores are typically used for thepurpose of accurately setting the gap length.

CITATION LIST Patent Literature PTL 1

-   Japanese Patent Application Laid-Open No. 2014-143439

SUMMARY OF INVENTION Technical Problem

Since heat is generated during operation of the apparatus, theabove-mentioned core is cooled by a cooling part provided in theapparatus; however, since it is difficult to uniformly cool the entiretyof the core, a temperature gradient occurs between a portion cooled bythe cooling part and other portions. As a result, a stress is applied tothe core due to heat generation in the core, and consequently the lossof the core is increased. As the loss of the core increases, the lossfurther increases the temperature gradient, and the loss of the corefurther increases.

In addition, in the case of the core having a plurality of legs such asthe E-shaped core, when the temperature gradient is further increasedand the stress is further applied between the legs, the core may bedamaged by the stress. In particular, in the configuration in which thecomponents are fixed so as to maintain the relative positions as in theconfiguration of the related art, the contact points of the componentsare completely fixed, and consequently the portions other than thecontact points may be damaged.

An object of the present disclosure is to provide a core that can reducean increase of the heat generation amount and an increase of the lossdue to a stress applied to the core.

Solution to Problem

A core according to an embodiment of the present disclosure includes awinding part where a winding is wound; and a wall part including a firstwall part, a second wall part spaced apart from the first wall part anddisposed opposite to the first wall part in a first direction, a thirdwall part in contact with the first wall part, and a fourth wall partspaced apart from the third wall part and disposed opposite to the thirdwall part in a second direction different from the first direction, thewall part surrounding the winding part.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide a corethat can reduce an increase of the heat generation amount and anincrease of the loss due to a stress applied to the core.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a core according to an embodiment ofthe present disclosure;

FIG. 2 is a diagram illustrating a state where the core is filled with apotting material;

FIG. 3 is a diagram for explaining an effect and an operation of thecore;

FIG. 4 is a diagram for explaining a problem with an E-shaped core;

FIG. 5 is a diagram illustrating an example of a core according to amodification;

FIG. 6 is a diagram illustrating an example of a core according to amodification;

FIG. 7 is a diagram illustrating an example of a core according to amodification;

FIG. 8 is a diagram illustrating an example of a core according to amodification;

FIG. 9 is a diagram illustrating an example of a core according to amodification;

FIG. 10 is a diagram illustrating an example of a core according to amodification; and

FIG. 11 is a diagram illustrating an example of a core according to amodification.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present disclosure will be described in detailbelow with reference to the drawings. FIG. 1 is a diagram illustratingcore 1 according to an embodiment of the present disclosure.

As illustrated in FIG. 1 , core 1 is, for example, a magnetic materialsuch as an iron core used in a transformer provided in a powerconversion apparatus such as a power supply apparatus, and core 1includes winding part 2 and wall part 3. Winding part 2 and wall part 3are composed of respective members that are separate from each other.Here, the separate members are members that are each independentlycomposed, and are not integrated with each other, and the separatemembers are not necessarily be composed of different materials.

Winding part 2 is a part where a winding (not illustrated) is wound, andextends in the vertical direction. The vertical direction corresponds tothe “first direction” of the present disclosure.

The end surface of the lower end portion of winding part 2 is in contactwith the upper surface of second wall part 32 (described later) in wallpart 3. The upper end portion of winding part 2 is disposed apart fromthe lower surface of first wall part 31 (described later) in wall part3.

Wall part 3 surrounds winding part 2 and has a rectangular shape. Wall 3includes first wall part 31, second wall part 32, third wall part 33 andfourth wall part 34. First wall part 31, second wall part 32, third wallpart 33 and fourth wall part 34 are composed of respective plate-shapedmembers that are separate members.

First wall part 31 and second wall part 32 are extended in the lateraldirection and disposed so as to sandwich winding part 2 in the verticaldirection. The lateral direction corresponds to the “second direction”of the present disclosure.

First wall part 31 is disposed on the upper end side of winding part 2.Second wall part 32 is disposed on the lower end side of winding part 2.

Third wall part 33 and fourth wall part 34 are extended in the verticaldirection and disposed so as to sandwich winding part 2 in the lateraldirection. Third wall part 33 and fourth wall part 34 are disposedbetween first wall part 31 and second wall part 32 in the verticaldirection.

Third wall part 33 is disposed on the right side of winding part 2, andfourth wall part 34 is disposed on the left side of winding part 2.

The end surface of the upper end portion of third wall part 33 is incontact with the lower surface of the right end portion of first wallpart 31. The end surface of the lower end portion of third wall part 33is in contact with the upper surface of the right end portion of secondwall part 32.

The end surface of the upper end portion of fourth wall part 34 is incontact with the lower surface of the left end portion of first wallpart 31. The end surface of the lower end portion of fourth wall part 34is in contact with the upper surface of the left end portion of secondwall part 32.

In addition, as illustrated in FIG. 2 , winding part 2 and wall part 3are fixed with potting material 4. Potting material 4 is provided insidewall part 3 together with winding part 2 and the winding.

In addition, second wall part 32 is a part that makes contact with acooling part 100 provided in an external apparatus such as a powerconversion apparatus. In other words, second wall part 32 is a portionto be cooled by the external cooling part. In addition, the end portionof winding part 2 located on the side of the portion to be cooled isdisposed in contact with wall part 3, and the end portion of windingpart 2 that is opposite to the portion to be cooled is spaced apart fromwall part 3.

An effect and an operation of core 1 according to the present embodimenthaving the above-described configuration are described below.

Core 1 generates heat during operation of the apparatus in which core 1is mounted. In the present embodiment, since second wall part 32 is aportion to be cooled, core 1 is cooled when the portion of second wallpart 32 is cooled. However, since the portions other than second wallpart 32 in core 1 are not in contact with the cooling part, the entirecore 1 is not uniformly cooled. Therefore, a temperature gradient occursbetween second wall part 32 and the other portions.

When such a temperature gradient occurs, a stress is applied to eachpart of core 1 due to the thermal expansion of the potting material 4.In addition, a stress is applied to each part of core 1 also due to thethermal expansion of wall part 3 itself. For example, as illustrated inFIG. 3 , in third wall part 33 and fourth wall part 34, outward stress Nis applied from the inside of wall part 3. In FIG. 3 , only the stress Napplied to third wall part 33 and fourth wall part 34 is illustrated asan example, and illustration of the stress applied to first wall part 31and second wall part 32 is omitted.

Such a stress N affects the magnetic field generated by the winding, andthe loss in core 1 increases. When the loss of core 1 increases, theheat generation amount increases as a result of the loss, andaccordingly the temperature gradient further increases. Then, the stressfurther increases, and consequently the loss of core 1 furtherincreases.

Here, for example, in the case of a configuration including an E-shapedcore A including main body part A1 and three leg parts A2, A3, and A4extending in the vertical direction from different portions of main bodypart A1 as illustrated in FIG. 4 , a stress N is applied between mainbody part A1 and each leg part and/or between two different leg parts.

Disadvantageously, such a configuration continuously increases the heatgeneration amount, the stress, and the loss, eventually breaking core A.

In contrast, in the present embodiment, the parts in wall part 3 areseparate members as illustrated in FIG. 3 . In other words, first wallpart 31, second wall part 32, third wall part 33 and fourth wall part 34are configured to be movable with thermal expansion of wall part 3.

Thus, each part slides along the direction of the stress applied to thepart (see arrows X1 and X2), and each part can relieve the stressapplied to each other. As a result, the influence of the stress can bereduced, and the increase of the heat generation amount and the increaseof the loss due to the stress can be reduced.

In addition, since winding part 2 is composed of a member separate fromwall part 3, the parts of wall part 3 and winding part 2 slide in thedirection of the stress applied thereto, and the stress can be relieved.As a result, the influence of the stress can be reduced, and thus, afurther increase of the heat generation amount and a further increase ofthe loss due to the stress can be reduced.

In addition, by reducing the increase of the heat generation amount andthe increase of the loss, the increase of the stress due them can besuppressed, and thus a situation where core 1 is damaged by the increaseof the stress can be suppressed.

In addition, since second wall part 32 is the portion to be cooled, thespacing between winding part 2 and first wall part 31 is located on theside opposite the cooling part. When winding part 2 and first wall part31 are in contact with each other, the heat generated in winding part 2is transmitted to first wall part 31. Since first wall part 31 islocated on the side opposite to second wall part 32 that is the portionto be cooled, first wall part 31 is difficult to be cooled. As such,when first wall part 31 is in contact with winding part 2, the coolingefficiency of the entire core 1 is reduced.

In contrast, in the present embodiment with the spacing between windingpart 2 and first wall part 31, the heat generated in winding part 2 isnot easily transmitted to first wall part 31. As a result, reduction inthe cooling efficiency of the entire core 1 is suppressed, and thus thecooling performance in core 1 is improved.

In addition, since winding part 2 and wall part 3 are fixed with pottingmaterial 4, winding part 2 and wall part 3 can be easily fixed. Inaddition, since the winding is also fixed with the potting material 4,it is not necessary to provide a bobbin and the like, for example. As aresult, the number of parts in core 1 can be reduced.

While third wall part 33 is in contact with the lower surface of firstwall part 31 and the upper surface of second wall part 32 in the aboveembodiment, the present disclosure is not limited thereto. For example,as illustrated in FIG. 5 , third wall part 33 may be in contact with theend surface of the right end portion and the end surface of the rightend portion of second wall part 32.

In addition, while fourth wall part 34 is in contact with the lowersurface of first wall part 31 and the upper surface of second wall part32 in the above embodiment, the present disclosure is not limitedthereto. For example, as illustrated in FIG. 5 , fourth wall part 34 maybe in contact with the end surface of the left end portion of first wallpart 31 and the end surface of the left end portion of second wall part32.

In addition, while the surface shape of each of first wall part 31,second wall part 32, third wall part 33 and fourth wall part 34 is arectangular shape in the above embodiment, the present disclosure is notlimited thereto. For example, as illustrated in FIG. 6 , the surfaceshape of each of first wall part 31, second wall part 32, third wallpart 33 and fourth wall part 34 may be a trapezoidal shape.

In addition, while wall part 3 is divided into four parts, namely, firstwall part 31, second wall part 32, third wall part 33 and fourth wallpart 34 in the above embodiment, the present disclosure is not limitedthereto. For example, as illustrated in FIG. 7 , the wall part mayinclude fifth wall part 5 and sixth wall part 6.

Fifth wall part 5 includes first extending part 51, and second extendingpart 52. First extending part 51 is extended in the lateral direction,and disposed above winding part 2. Second extending part 52 is extendeddownward from the right end portion of first extending part 51 anddisposed on the right side of winding part 2. First extending part 51corresponds to the “first wall part” of the present disclosure. Secondextending part 52 corresponds to the “third wall part” of the presentdisclosure.

As with fifth wall part 5, sixth wall part 6 includes first extendingpart 61 and second extending part 62. First extending part 61 isextended in the lateral direction, and disposed below winding part 2.Second extending part 62 is extended upward from the left end portion offirst extending part 61 and disposed on the left side of winding part 2.First extending part 61 corresponds to the “second wall part” of thepresent disclosure. Second extending part 62 corresponds to the “fourthwall part” of the present disclosure. That is, in the above embodiment,the combination of first wall part 31 and third wall part 33, and thecombination of second wall part 32 and fourth wall part 34 may each beintegrally configured in an L-shape. By forming the core in an L-shape,the increase of the heat generation amount and the increase of the lossdue to the stress applied thereto can be reduced.

Specifically, second extending part 52 of fifth wall part 5 makescontact with the upper surface of the right end portion of firstextending part 61 of sixth wall part 6. Second extending part 62 ofsixth wall part 6 makes contact with the lower surface of the left endportion of first extending part 51 of fifth wall part 5. Winding part 2is disposed on the upper surface of first extending part 61 of sixthwall part 6. Potting material 4 is supplied in the space surrounded byfifth wall part 5 and sixth wall part 6.

With such a configuration, when a rightward stress is applied from theinside of fifth wall part 5, fifth wall part 5 slides to the right sidealong the direction of the stress, for example. In addition, when aleftward stress is applied from the inside of sixth wall part 6, sixthwall part 6 slides to the left side along the direction of the stress,for example.

That is, even with such a configuration, the influence of the stress canbe reduced, and thus the increase of the heat generation amount and theincrease of the loss due to the stress can be reduced.

In addition, one of fifth wall part 5 and sixth wall part 6 may beincluded in the wall part. For example, as illustrated in FIG. 8 , thewall part may include first wall part 31 and third wall part 33 of theconfiguration illustrated in FIG. 1 and the like, and sixth wall part 6illustrated in FIG. 6 . That is, in the above embodiment, thecombination of first wall part 31 and third wall part 33, or thecombination of second wall part 32 and fourth wall part 34 may beintegrally configured in an L-shape. FIG. 8 illustrates a core in whichsecond wall part 32 and fourth wall part 34 are integrated with eachother.

However, since fifth wall part 5 or sixth wall part 6 has theconfiguration in which the first extending part and the second extendingpart are connected to each other, a stress may be applied to each otherbetween the first extending part and the second extending part. As such,if possible, it is preferable to adopt the configuration in which thewall part is divided into each side as in the configuration illustratedin FIG. 1 or the like.

In addition, at least one of first wall part 31, second wall part 32,third wall part 33 and fourth wall part 34 may be further divided into aplurality parts. In this case, the plurality of divided parts of firstwall part 31, second wall part 32, third wall part 33 and fourth wallpart 34 may not have a linear shape.

In addition, while winding part 2 and wall part 3 are composed ofrespective separate members in the above embodiment, the presentdisclosure is not limited thereto. For example, as illustrated in FIG. 9, the winding part and the wall part may be integrated with each other.

In this configuration, second wall part 32 of wall part 3 includeswinding part 32A. Winding part 32A extends upward from a central portionin the lateral direction in the upper surface of second wall part 32.The upper end portion of winding part 32A is spaced apart from firstwall part 31.

Even with such a configuration, the influence of the stress can bereduced, and thus the increase of the heat generation amount and theincrease of the loss due to the stress can be reduced.

Incidentally, since winding part 32A is integrated with second wall part32 in this configuration, the stress resulting from expansion of pottingmaterial 4 is applied also to winding part 32A. As such, it ispreferable to adopt a configuration that can release the stress appliedto the entire core 1 in the range sandwiched between winding part 32A,third wall part 33 and fourth wall part 34 as much as possible.

Specifically, it is preferable that the contact points between secondwall part 32, third wall part 33 and fourth wall part 34 be locatedwithin the range of winding part 32A in the vertical direction, and itis more preferable that the contact points are located at the sameposition as the base end portion of winding part 32A in the verticaldirection. The base end portion of winding part 32A in the configurationillustrated in FIG. 9 is the lower end portion of winding part 32A, andis located at the same position as the contact points of second wallpart 32, third wall part 33 and fourth wall part 34 in the verticaldirection.

As a result, third wall part 33 and fourth wall part 34 are movable inthe range between winding part 32A, third wall part 33 and fourth wallpart 34, and thus the stress is easily relieved.

In addition, as illustrated in FIG. 10 , first wall part 31 may includewinding part 31A. In this configuration, first wall part 31 includeswinding part 31A, and second wall part 32 includes winding part 32A.Winding part 31A extends downward from the lower surface of first wallpart 31, and faces winding part 32A of second wall part 32. Winding part32A of second wall part 32 is shorter in comparison with theconfiguration illustrated in FIG. 9 .

In addition, while the winding part and the wall part are fixed with thepotting material in the above embodiment, the present disclosure is notlimited to this. For example, as illustrated in FIG. 11 , the contactpoints between each part may be fixed with adhesive 7 such that theparts are fixed.

Note that adhesive 7 is required to have a melting point (softeningpoint) at which adhesive 7 is softened and the fixed state is releasedwhen core 1 generates heat during the operation of the apparatus.Otherwise, when wall part 3 is thermally expanded due to the stressapplied to each part, each part cannot be moved, and consequently theincrease of the heat generation amount and the increase of the loss dueto the stress cannot be reduced.

In addition, in the case where the apparatus in which the transformer ismounted does not need to fix the core with a potting material, anadhesive, or the like, each part of the wall part may be fixed with afixing member such as a clip. However, it is necessary that the fixingmember has a fixing force that allows for movement of each part when thewall part is thermally expanded.

In addition, while wall part 3 has a rectangular shape in the aboveembodiment, the present disclosure is not limited thereto, and may havea shape other than a rectangular shape.

In addition, any of the above-described embodiments is merely an exampleof a specific embodiment for implementing the present disclosure, andthe technical scope of the present disclosure should not be construed asbeing limited by these embodiments. That is, the present disclosure maybe embodied in various forms without departing from the spirit oressential characteristics thereof.

While various embodiments have been described herein above, it is to beappreciated that various changes in form and detail may be made withoutdeparting from the spirit and scope of the invention(s) presently orhereafter claimed.

This application is entitled and claims the benefit of Japanese PatentApplication No. 2019-115485, filed on Jun. 21, 2019, the disclosure ofwhich including the specification, drawings and abstract is incorporatedherein by reference in its entirety.

INDUSTRIAL APPLICABILITY

The core of the present disclosure is useful as a core that can reducethe increase of the heat generation amount and the increase of the lossdue to a stress applied to the core.

1. A core comprising: a winding part where a winding is wound; and awall part including a first wall part, a second wall part spaced apartfrom the first wall part and disposed opposite to the first wall part ina first direction, a third wall part in contact with the first wallpart, and a fourth wall part spaced apart from the third wall part anddisposed opposite to the third wall part in a second direction differentfrom the first direction, the wall part surrounding the winding part,wherein: the winding part is spaced apart from the first wall part, thethird wall part and the fourth wall part, the first wall part, thesecond wall part, the third wall part, and the fourth wall part areseparate from each other, the winding part extends in the firstdirection between a contact point between the second wall part and thethird wall part, and a contact point between the second wall part andthe fourth wall part, a distance between an external cooling part andthe first wall part is greater than a distance between the externalcooling part and the second wall part a space between the winding partand the first wall part is closer to the first wall part than to thesecond wall part in the first direction; and the winding part is spacedapart from the first wall part, the third wall part and the fourth wallpart.
 2. The core according to claim 1, wherein the first wall part, thesecond wall part, the third wall part, and the fourth wall part areconfigured to be movable with thermal expansion of the wall part.
 3. Thecore according to claim 1, wherein the third wall part is configured tobe movable with respect to the first wall part and the second wall part;and the fourth wall part is configured to be movable with respect to thefirst wall part and the second wall part.
 4. The core according to claim1, wherein the second wall part is configured to be movable with respectto the third wall part and the fourth wall part.
 5. The core accordingto claim 2, wherein the third wall part is configured to be movable withrespect to the first wall part and the second wall part; and the fourthwall part is configured to be movable with respect to the first wallpart and the second wall part.
 6. The core according to claim 1, whereinthe second wall part contacts the external cooling part.
 7. The coreaccording to claim 4, wherein the second wall part contacts the externalcooling part.